Performance Improvement of a Two-Stage Proportional Valve With Internal Hydraulic Position Feedback

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
He Wang ◽  
Xiaohu Wang ◽  
Jiahai Huang ◽  
Long Quan
Keyword(s):  
Performance Improvement ◽  
Control Strategy ◽  
Dead Zone ◽  
Poor Performance ◽  
Main Stage ◽  
Two Stage ◽  
Proportional Valve ◽  
Loop Control ◽  
Position Feedback ◽  
Performance Constraint

Abstract The present research concentrates on the performance improvement of a two-stage proportional valve with internal hydraulic position feedback which is named as the Valvistor valve. In this paper, the performance constraint of this valve is identified and a novel electronic closed-loop control strategy with an integral-separation fuzzy proportional-integral-derivative controller is proposed to improve the valve performance, including the static characteristics and the dynamic characteristics. The results show that in the Valvistor valve, the comparison point and the feedback loop for the internal hydraulic position feedback is only in the main stage, while the input is in the pilot stage. This leads to the poor performance of this valve. The control strategy is very effective and the performance of the Valvistor valve is improved. With the control strategy, the error of the poppet displacement is reduced from 4.9% to 2.1% by adjusting the spool displacement in the pilot stage in real-time and the flow error is reduced from 5.3% to 2.3%. The dead zone of the poppet displacement and the flow is eliminated. The hysteresis is reduced from 5.3% to 2.6% and the linearity is improved. The overshoot is reduced from 0.06 to 0.02 mm and the settling time is reduced from 0.5 to 0.2 s. Moreover, the bandwidth is increased from 8 to 16 Hz.

Inner-Loop Feedback for Deadband Compensation in Electromechanical Flight Surface Actuation Systems

2005 ◽  
Author(s):  
S. R. Habibi ◽  
J. Roach ◽  
G. Luecke
Keyword(s):  
Control Strategy ◽  
Dead Zone ◽  
High Gain ◽  
Velocity Control ◽  
Loop Control ◽  
Aerospace Sector ◽  
Loop Feedback ◽  
Actuation Systems ◽  
Simulated Analysis

This manuscript pertains to the application of an inner-loop control strategy to electro-mechanical flight surface actuation systems. Modular Electro-Mechanical Actuators (EMA) are increasingly used in-lieu of centralized hydraulics for the control of flight surfaces in the aerospace sector. The presence of what is termed as a dead zone in these actuators significantly affects the maneuverability, stability, and the flight profiles of aircrafts that use this actuation concept. The hypothesis of our research is that flight surface actuation systems may be desensitized to the effects of dead zone by using a control strategy with multiple inner-loops. The proposed strategy involves: high-gain inner-loop velocity control of the driving motor; and inner-loop compensation for the differential velocity between the motor versus the aileron. Our results indicate that this strategy is very effective and that it can considerably improve the system’s performance. The above hypothesis is confirmed by theoretical and simulated analysis using the model of an EMA flight surface actuator.

scholarly journals Inner-Loop Control for Electromechanical (EMA) Flight Surface Actuation Systems

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Saeid Habibi ◽  
Jeff Roach ◽  
Greg Luecke
Keyword(s):  
Control Strategy ◽  
Dead Zone ◽  
High Gain ◽  
Crossover Frequency ◽  
Velocity Control ◽  
Electromechanical Actuators ◽  
Loop Control ◽  
Input Signals ◽  
Aerospace Sector ◽  
Actuation Systems

This manuscript pertains to the application of an inner-loop control strategy to electromechanical flight surface actuation systems. Modular electromechanical actuators (EMAs) are increasingly used in lieu of centralized hydraulics for the control of flight surfaces in the aerospace sector. The presence of what is termed as a dead zone in these actuators significantly affects the maneuverability, stability, and the flight profiles of aircrafts that use this actuation concept. The hypothesis of our research is that flight surface actuation systems may be desensitized to the effects of dead zone by using a control strategy with multiple inner loops. The proposed strategy involves (a) high-gain inner-loop velocity control of the driving motor and (b) inner-loop compensation for the differential velocity between the motor versus the aileron. The above hypothesis is confirmed by theoretical and simulated analyses using the model of an EMA flight surface actuator. Our results indicate that for small input signals, this strategy is very effective and that it can (a) considerably increase the bandwidth and the crossover frequency of the system and (b) considerably improve the time response of the system. Further to this analysis, this manuscript presents guidelines for the design of EMA systems.

scholarly journals Research on control strategy of VIENNA rectifier based on electric vehicle DC charging module

2021 ◽  
Vol 2125 (1) ◽  
pp. 012010
Author(s):  
Shou-Zhong Lei ◽  
Qi-Gong Chen ◽  
Wei Xie
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Dead Zone ◽  
Dynamic Performance ◽  
Current Loop ◽  
Loop Control ◽  
Vienna Rectifier ◽  
Response Capability

Abstract Because the VIENNA rectifier has fewer switching devices, a high power factor and no need to set dead zone time, the front rectifier of the DC charging module of ev mostly uses VIENNA circuit. However, the DC charging module has higher requirements on the dynamic response capability and stability of the VIENNA rectifier system. The traditional PI double closed loop control strategy has poor dynamic response capability. For this reason, a hybrid control strategy of PI control for current loop and sliding mode control for voltage loop is used to control the VIENNA rectifier to improve the dynamic response and stability of the system. Finally, through the simulation of the rectifier circuit, and the comparison of the simulation results, it can be proved that the dynamic response ability and stability of the hybrid control strategy is relatively good. Finally, a simulation model of VIENNA rectifier is built, and the hybrid control strategy is proved to have good dynamic performance and stability by comparison.

scholarly journals Flow Control for a Two-Stage Proportional Valve with Hydraulic Position Feedback

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
He Wang ◽  
Xiaohu Wang ◽  
Jiahai Huang ◽  
Long Quan
Keyword(s):  
Mathematical Model ◽  
Flow Control ◽  
Control Method ◽  
Two Stage ◽  
Proportional Valve ◽  
Load Pressure ◽  
Flow Fluctuation ◽  
Position Feedback ◽  
Proportional Flow ◽  
Flow Valve

AbstractThe current research mainly focuses on the flow control for the two-stage proportional valve with hydraulic position feedback which is named as Valvistor valve. Essentially, the Valvistor valve is a proportional throttle valve and the flow fluctuates with the change of load pressure. The flow fluctuation severely restricts the application of the Valvistor valve. In this paper, a novel flow control method the Valvistor valve is provided to suppress the flow fluctuation and develop a high performance proportional flow valve. The mathematical model of this valve is established and linearized. Fuzzy proportional-integral-derivative (PID) controller is adopted in the closed-loop flow control system. The feedback is obtained by the flow inference with back-propagation neural network (BPNN) based on the spool displacement in the pilot stage and the pressure differential across the main orifice. The results show that inference with BPNN can obtain the flow data fast and accurately. With the flow control method, the flow can keep at the set point when the pressure differential across the main orifice changes. The flow control method is effective and the Valvistor valve changes from proportional throttle valve to proportional flow valve. For the developed proportional flow valve, the settling time of the flow is very short when the load pressure changes abruptly. The performances of hysteresis, linearity and bandwidth are in a high range. The linear mathematical model can be verified and the assumptions in the system modeling is reasonable.

scholarly journals Double Closed-Loop Compound Control Strategy for Magnetic Liquid Double Suspension Bearing

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1195
Author(s):  
Jianhua Zhao ◽  
Yongqiang Wang ◽  
Xuchao Ma ◽  
Sheng Li ◽  
Dianrong Gao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Electromagnetic Force ◽  
Closed Loop ◽  
Static Characteristic ◽  
Magnetic Liquid ◽  
Initial Current ◽  
Electromagnetic System ◽  
Initial Flow ◽  
Hydrostatic Force ◽  
Position Feedback

As a new type of suspension bearing, the magnetic liquid double suspension bearing (MLDSB) is mainly supported by electromagnetic suspension and supplemented by hydrostatic support. At present, the MLDSB adopts the regulation strategy of “electromagnetic-position feedback closed-loop, hydrostatic constant-flow supply” (referred to as CFC mode). In the equilibrium position, the external load is carried by the electromagnetic system, and the hydrostatic system produces no supporting force. Thus, the carrying capacity and supporting stiffness of the MLDSB can be reduced. To solve this problem, the double closed-loop control strategy of “electromagnetic system-force feedback inner loop and hydrostatic-position feedback outer loop” (referred to as DCL mode) was proposed to improve the bearing performance and operation stability of the MLDSB. First, the mathematical models of CFC mode and DCL mode of the single DOF supporting system were established. Second, the real-time variation laws of rotor displacement, flow/hydrostatic force, and regulating current/electromagnetic force in the two control modes were plotted, compared, and analyzed. Finally, the influence law of initial current, flow, and controller parameters on the dynamic and static characteristic index were analyzed in detail. The results show that compared with that in CFC mode, the displacement in DCL mode is smaller, and the adjustment time is shorter. The hydrostatic force is equal to the electromagnetic force in DCL mode when the rotor returns to the balance position. Moreover, the system in DCL mode has better robustness, and the initial flow has a more obvious influence on the dynamic and static characteristic indexes. This study provides a theoretical basis for stable suspension control and the safe and reliable operation of the MLDSB.

Sign in / Sign up

Export Citation Format

Share Document